Book Image

Mastering JavaScript Functional Programming

By : Federico Kereki
Book Image

Mastering JavaScript Functional Programming

By: Federico Kereki

Overview of this book

Functional programming is a programming paradigm for developing software using functions. Learning to use functional programming is a good way to write more concise code, with greater concurrency and performance. The JavaScript language is particularly suited to functional programming. This book provides comprehensive coverage of the major topics in functional programming with JavaScript to produce shorter, clearer, and testable programs. You’ll delve into functional programming; including writing and testing pure functions, reducing side-effects, and other features to make your applications functional in nature. Specifically, we’ll explore techniques to simplify coding, apply recursion for loopless coding, learn ways to achieve immutability, implement design patterns, and work with data types. By the end of this book, you’ll have developed the JavaScript skills you need to program functional applications with confidence.
Table of Contents (22 chapters)
Title Page
About the Author
About the Reviewer
Customer Feedback
Connecting Functions - Pipelining and Composition
Answers to Questions

Chapter 3. Starting Out with Functions - A Core Concept

In chapter 2 Thinking Functionally - A First Example, we went over an example of FP thinking, but let's now go to the basics, and review functions. In Chapter 1, Becoming Functional - Several Questions, we mentioned that two important JS features were functions as first-class objects and closures. Now, in this chapter, let's:

  • Examine some key ways of defining functions in JS
  • Go in detail regarding arrow functions, which are closest to the lambda calculus functions
  • Introduce the concept of currying
  • Revisit the concept of functions as first-class objects

We'll also consider several FP techniques, such as:

  • Injection, as needed for sorting with different strategies and other uses
  • Callbacks and promises, introducing the continuation passing style
  • Polyfilling and stubbing
  • Immediate invocation schemes